Floor maintenance machine having



Feb. 7, 1956 w HOLT 2,733,465

FLOOR MAINTENANCE MACHINE HAVING ELECTRICAL GROUND CONNECTION Filed July 10, 1951 M W! J 2 mm 25 I ln24 20 M 3/ 42 WII y #30 I 50 WW 1 I W 1M1 32 33 d X Walk/M ,Wu .0. i N m, "X

43 23 FIG.2 47 43 INVENTOR ZWZ/iamif/o/f ATTO RNEY FLOOR MAINTENANCE MACHINE HAVING ELECTRICAL GROUND CONNECTION William. E. HOII, Oakland, Caiit'. Application July 10, 1951, Serial No. 236,007

3 Claims. (CI. 15 49) The present invention relates to the construction andoperationof floor maintenance machines, and. more particularly to machines of the: character described comprising a motor driven floor surfacing. element arranged to rotate about a vertical axis when. in use.

The rotary surfacing element of such machines normally consists of a brush member having an' annular wooden base detachably secured in a predetermined posi tionv to a reversible rotary drive element and in which base tufts of bristles or fiber are embedded. in any suitable manner. The tufts are initially positioned. and trimmed to provide a level brushing surface as well as to dynamically balance the brush member. If however the tufts are improperly trimmed or wear unevenly or tufts are lost, the brush member is thrown out of dynamic balance and tends to wobble relative to the drive mechanism. The effect is usually cumulative and tends to cause rapid and uneven wearing of the tufts. Also when ma.- chines of this type are used on rough or irregular floor surfaces, the brush member often tends to whip or hop, producing an uneven surfacing effect and imposing. uncle sirable torque stresses on the drive mechanism. This. is particularly likely to occur when the surfacing element is capable of being reversed in direction.

It has been found that in machines of this type charges of static electricity tend to build up in the machine metal parts during operation which cause considerable annoy ance to the operator.

The object of my invention is the provision of a floor maintenance machine of the character described with a rotary surfacing element and connecting bracket construction affording an effective and easily assembled ground connection for the metal parts of the machine at low cost.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawing and descriptive matter in which I have illustrated and described a preferred embodiment of my invention.

Of the drawings:

Fig. 1 is an elevation of a portion of a floor mainten ance machine of the general type to which my invention is applied;

Fig. 2 is an enlarged view of portions of the drive mechanism and brush member, with parts broken away and in section; and

Fig. 3 is a bottom perspective of the brush connecting bracket.

In the floor maintenance machine illustrated a wheeled carriage is formed by an annular downwardly flaring housing 10, on the rear side of which a pair of supporting wheels 11 are tiltably mounted. An inclined tiltable socket 12 projects rearwardly from the housing and receives a hollow adjustable handle member 13 by which the machine is directed by the operator. A reversible 2,733,465 Patented Feb. 7, 1956 ice 2v electric motor is mounted within the housing 10 and arranged with its drive shaft 20 vertical and symmetri cally projecting downwardly through the center opening in the housing 10. A downwardly tapering stepped shell 21 surrounds the shaft 20 and is formed with a horizontal annular flange 22 at its upper end which is ro' tatably supported on the housing 10. The shell has a bottom section 23 inwhich a hub 24 is formed. Thehub. serves as a journal for the lower end of the drive shaft 20. Rotation of the shell is effected by" a spur gear 25 on the shaft 20 driving an internal ring gear 26 on the shell through idler gears 27 in a well known manner.

The rotary surfacing element shown is a brush mem" ber 30 comprising an annular wooden base 31 in which a multiplicity of tufts 32 of fiber or bristles are embedded and trimmed to form a level brushing surface. In ad cordance with my invention, a readily detachable driveconnection between the lower section 23 of the rotary shell and the brush member 30 is established by a special bracket 49 which fits into the circular opening 33 in the base 31 and is supported in that position by projecting flanges 41 which rest on and are secured to the upper sur face of the wooden base by screws 42. At three sym' metrically spaced points on the underside of the bracket substantially opposite to alternate flanges 41, integral lugs or stop members 43 extend downwardly. The logs have flat vertical converging faces 44 on opposite sides thereof. At symmetrically arranged points intermediate each pair of lugs 43, the inner edge of the bracket is cut away to form outwardly tapered recesses 45. Between each of the recesses 45 and the adjacent lug faces 49 is a relatively stiff flat spring 46 secured at one end to the underside of the bracket adjacent the corresponding recess and with its free end downwardly bent away from the bracket in an inclined plane and terminating adjacent the corresponding lug face 44. At symmetrically spaced points on the periphery of the lower shell section 23 cor responding to the location of the recesses 45, short in tegral lugs 47 of substantially rectangular cross-section and a shape permitting passage through the recesses 45, project from the shell with their upper surfaces at a level intersecting the inclined portion of the springs 46.

With the described construction, the brush member 30 is readily mounted in the machine by tilting the ma chine and positioning the bracket recesses 45 so as to pass over the lugs 47 and then angularly moving the brush member counter to the intended direction of brush rotation until the lugs 47 pass under and in resilient contact with a corresponding spring 46 until they abut the adjacent faces 44 of the corresponding stop members 43. In this position, the upper surface of the bracket will be in contact with the peripheral flange on the shell section 23 and the springs 46 will exert a downward pressure on the drive lugs 47. In detaching the brush member, the operation is reversed.

With the described drive connection between the motor 15 and the brush member 30, a positive drive is effected in either direction of rotation of the brush, while at the same time the resilient support of the brush member on the drive lugs 47 permits a limited movement of the brush member vertically relative to the shell 21 without disrupting the drive connection. This capacity for limited relative vertical movement between these parts allows the brush member to effect the desired surfacing action on rough or uneven floor surfaces without whipping and hopping. The resilient vertical contact of the parts tends to maintain the brushing surface in the same plane for all normal variations in tuft wear. Torque stress is kept to a minimum, insuring a long life to both the brush member and machine.

The described rotary brush and supporting bracket construction also facilitates the inclusion and assembly of an electrical ground connection between the metal parts 7 of the machine and the surface contacting with the brush. For this purpose a small diameter hole 50 is drilled through 'the wooden base of the brush opposite one of openings in a flange 41 arranged to receive one of the fastening screws 42. A tuft 51 of flexible wires of a metal, such as copper, having a high electrical conductivity but of sufficient softness not to mark the floor surface is inserted through the hole 50 before the screws 42 are inserted. The tuft 51 is held in position by being Wound around the shank of the screw between the screw head and brush base 31. The lower end of the wire tuft 51 extends slightly below the brush tufts 32, as shown in Fig. 2. With this arrangement, an electrical ground connection is provided for the metal parts of the machine which effectively dissipates any static charges accumulating in those parts.

While in accordance with the provisions of the statutes I have illustrated and described herein the best form of the invention now known to me, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention covered by my claims, and that certain features of my invention may sometimes be used to advantage without a corresponding use of other features.

I claim:

1. A floor maintenance machine comprising an electric motor, a rotary brush rotatable in a horizontal plane about a vertical axis and comprising a base of non-metallic material and a multiplicity of vertically arranged tufts of non-metallic bristles carried thereby, means forming tric motor, a rotary brush rotatable in a horizontal plane about a vertical axis and comprising a wooden base and a multiplicity of vertically arranged tufts of non-metallic bristles carried thereby, means forming a drive connection between said motor and said rotary brush including a rotary metallic member driven by said motor, a plurality of peripheral metallic lugs projecting from said rotary member, a metallic bracket mounted on said rotary brush and having recesses therein adapted to receive said lugs, and a tuft of wires of metal capable of conducting electricity and extending through said rotary brush parallel to said tufts of bristles, said tuft of wires being electrically connected to said bracket to form an electrical ground connection for the metal parts of said machine.

3. A floor maintenance machine comprising an electric motor, a rotary brush rotatable in a horizontal plane about a vertical axis and comprising a wooden base and a multiplicity of vertically arranged tufts of non-metallic bristles carried thereby, means forming a drive connection between said motor and said rotary brush including a rotary metallic member driven by said motor, a plurality of peripheral metallic lugs projecting from said rotary member, a metallic bracket mounted on said rotary brush and having recesses therein adapted to receive said lugs, and a tuft of wires of metal capable of conducting electricity and extending through said rotary brush parallel to said tufts of bristles, said tuft of wires being arranged adjacent the center of said brush and electrically connected to said bracket to form an electrical ground connection for the metal parts of said machine.

References Cited in the file of this patent UNITED STATES PATENTS 1,393,332 Wimmer Oct. 11, 1921 2,026,006 Wennerstrom Dec. 31, 1935 2,155,172 Sklar Apr. 18, 1939 2,449,972 Beach Sept. 28, 1948 2,524,995 Sassano Oct. 10, 1950 2,561,279 Holt July 17, 1951 

